Having by this means found the true distance of the Moon, and having observed well the _apparent Diameter_ of it at that time with a good _Telescope_, it is easie enough, by one single Observation of the apparent Diameter of the Moon with a good Glass, to determine her distances in any other part of her _Orbit_, or _Dragon_, and consequently, some few Observations will tell us, whether she be mov’d in an _Ellipsis_, (which, by the way, may also be found, even now, though I think we are yet ignorant of her true distance) and next (which without such Observations, I think, we shall not be sure of) we may know exactly the bigness of that _Ellipsis_, or Circle, and her true velocity in each part, and thereby be much the better inabled to find out the true cause of all her Motions. And though, even now also, we may, by such Observations in one station, as here at _London_, observe the _apparent Diameter_ and motion of the Moon in her _Dragon_, and consequently be inabled to make a better ghess at the _Species_ or kind of Curve, in which she is mov’d, that is, whether it be sphærical, or _elliptical_, or neither, and with what proportional velocities she is carried in that Curve; yet till her true _Parallax_ be known, we cannot determine either. Next, for the true distance of the Sun, the best way will be, by accurate Observations, made in both these forementioned stations, of some convenient Eclipse of the Sun, many of which may so happen, as to be seen by both; for the _Penumbra_ of the Moon may, if she be sixty Semidiameters distant from the Earth, and the Sun above seven thousand, extend to about seventy degrees on the Earth, and consequently be seen by Observators as far distant as _London_, and St. _Helena_, which are not full sixty nine degrees distant. And this would much more accurately, then any way that has been yet used, determine the Parallax, and distance, of the Sun; for as for the Horizontal Parallax I have already shewn it sufficiently uncertain; nor is the way of finding it by the Eclipse of the Moon any other then hypothetical; and that by the difference of the true and apparent quadrature of the Moon is not less uncertain, witness their Deductions from it, who have made use of it; for _Vendeline_ puts that difference to be but 4′.30″. whence he deduces a vast distance of the Sun, as I have before shewn. _Ricciolo_ makes it full 30′.00. but _Reinoldus_, and _Kircher_, no less then three degrees. And no wonder, for if we examine the _Theory_, we shall find it so complicated with uncertainties.